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India's caste system - the oldest social order in the world - divides society into four castes, and thousands of subcastes - based on traditional occupations. Below the four castes are the "untouchables" (now known as Dalits) like Sister Sudha Varghese's students, whose traditional occupations are deemed so polluting that religious doctrine said they could not share food or dishes with caste Hindus, use the same barber or laundry, or enter their homes. Discrimination based on caste was outlawed more than 60 years ago, but the system endures and continues to shape life in much of India, especially rural areas.

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Annie Namala is a Dalit activist who works to end caste discrimination and directs the Centre for Social Equity and Inclusion in New Delhi. We sent her your questions about caste. Here's what she had to say.

Q: This may be a naive question, but how are members of a caste identifiable? As in, how do children learn to recognize people from different castes? If it is due to surname, what's to stop people from just changing their name and lying about their caste? – Jessica Ellis

A: In general it is difficult for any outside person to identify the caste of a person, as it is based on particular features or skin colour. As insiders we recognise the caste of the other person through surname, family and village connections, food habits, rituals and ceremonies and general enquiry into one’s family and background. It is not offensive for people to even directly ask about one’s caste affiliation in India.

One identifies one’s caste in government records to access affirmative action and is a category in most government records. While more generic names are being adopted now particularly for the younger generations, changing names or hiding surnames is a superficial and temporary way of denying ones caste identify. It may invite more humiliation and violence when it is ultimately recongised, which happens in many cases.

Q: What kinds of health services or welfare programs does the government provide for Mushahar/Dalit people? I noticed they had good teeth in the photos. – Andrew

A: There is an extensive health care system designed under the government, with health outposts, primary health care centres and referral centres. The state health care system is starved of funds, skilled personnel and adequate infrastructure, which results in about 80 per cent of the health costs being “out of pocket” expenses even for the poor.

Parallel is the highly costly and state-of-the-art private health care system where even people from other countries seek treatment. In addition to the lack of various facilities, those from the Dalit and Mushahar communities also face discrimination with health care personnel refusing them treatment, providing poor treatment and outright discriminating against them in treatment. While a number of studies report the deplorable conditions of the government-managed health care system, some also report on discrimination issues.

Q: Is it only people in the worst caste who are shunned? Are all other castes now intermingling, intermarrying and facing no barriers? Or do barriers exist between all castes? – Jeanette Falkenstein

A: Various levels of barriers and disabilities are built into the caste system as mentioned earlier in a graded manner. Thus while greater inter-mingling is possible above the line of touchability, issues like inter-caste marriages are not commonly accepted. One may have to pay with one’s life for intercaste marriage, especially if it is across the touchability line. The Supreme Court of India has come down strongly against honour killings more recently.

Q: Women's rights seem paramount for improving the lives of these people. What access do they have to birth control? Are there cultural or social barriers as well? – Andrew

A: Gender equations here too are skewed against women as in most societies and women in general have little say on reproductive issues. In addition there are strong pressures on women to marry early, have children immediately, that these decisions are most often taken by the husband and family than the women themselves. While there are no cultural barriers against birth control, the poor access to health care, lack of information and the absence of health personnel to guide them give women very little real choice or opportunity, particularly in the remote rural areas or urban poor areas to which the Mushahar community belongs.